The present invention relates to an extracting tool for removing a plug-in module board from a module mounting frame and, more particularly, to an extracting tool which can apply a large extracting force due to mechanical advantage applied by the extractor.
There is a constant demand for smaller electrical and electronic components, particularly in the aircraft and missile fields, as weight is of extreme importance. One concept of microelectronics which has been recently developed and which offers a great reduction in size and weight of electronic units is that of integrated circuitry which is formed on insulated bases such as glass, fused silica, or ceramic substrates. Integrated circuitry includes a number of active and passive components which are fabricated by one or more of a combination of several thin film deposition techniques onto a glass or ceramic substrate.
In order to reduce costs, expedite production, and provide a reliable electronic component, the Department of the Navy, as well as other military branches, have been engaged in a standard hardware program in which electronic plug-in modules have been developed which are capable of meeting various system requirements. Generally, a plug-in module is designed for high reliability and, whenever possible, have a cost which will permit them to be thrown away rather than be repaired. One such plug-in module is shown in U.S. Pat. No. 3,243,660, entitled "Electronic Module Assembly", which issued Mar. 29, 1966, to Leonard J. Yuska and David P. Zimmerman.
One concept of a standard hardware program is to have a plurality of modules which plug-in a chassis to form an assembly and normally these plug-in modules slide in grooves or ways in the chassis and engage a mating female connector. As the basic module connector consists of 40 metal bayonet pins, removal of a plug-in module from a chassis normally presents a problem, as any lateral movement could damage the small bayonet pins.
Various pulling tools or extractors have been devised to facilitate the removal of a plug-in module from a chassis, and these tools are designed so that an operator can withdraw the module with controlled force. One such device which has been developed for the Navy hardware program is shown in U.S. Pat. No. 3,180,670, entitled "Chassis Pulling Tool", which issued Apr. 27, 1965, to Thomas R. Pryde. In this chassis pulling tool, first and second U-shaped members are provided, with the legs of an inner U-shaped member being slidably mounted through holes in an outer U-shaped member. The legs of the inner U-shaped member are constructed and arranged so as to engage a plug-in module which is to be removed from a chassis.
While the chassis pulling tool of the above-mentioned patent permits an operator to easily withdraw a plug-in module from a chassis, the chassis pulling tool is lacking in universal application and will operate with only one specific design. In order to eliminate the necessity of having a multiple number of pulling tools of various sizes, a universal extractor tool was developed for the standard hardware program. This tool is shown and described in U.S. Pat. No. 3,484,129, entitled, "Universal Extractor Tool" which issued Dec. 16, 1969, to Sherman G. Askren. This patented universal extractor tool eliminates the necessity of having a multiple number of extracting tools, however, it has one disadvantage. It has been determined that an extraction force of about 27 pounds is required to remove some types of plug-in modules from a chassis and, when this force is applied by the extractor tool, there is propensity for the module to accelerate violently upon release of contact pins from their sockets and to decelerate even more violently when the sliding portion of the tool reaches the tool stops. The reversed high G-force can be detrimental to the rather fragil module.
The universal extractor tool shown and described in U.S. Pat. No. 3,759,559, which issued Sept. 18, 1973, to Leonard J. Yuska, overcame the deficiency described for the extractor shown in U.S. Pat. No. 3,484,129, by providing first and second resistive forces provided by a non-metallic material, that is, a resilient cushion which is provided with a wide slot thereby forming an elongated oval shaped cushion. A relatively small force is required to move a slidable extracting member until the slot becomes closed and then a greater force is required for additional movement.
The extracting tools shown and described in U.S. Pat. Nos. 3,484,129 and 3,759,559, are designed for operation by an operator using one hand, and sufficient force can be applied to separate a 40-pin male connector from a mating female connector. Recently, however, the standard hardware program conducted by the Department of the Navy, has been considering expanding to use 100, and even 200, pin connectors, and it has already been determined that a one-hand, squeeze-type extractor will not supply sufficient force to separate the male and female connectors.